Force Plates v. AMI: How do they compare?

Force Plates v. The AMI

When discussing the Athletic Movement Index (AMI) with potential clients, our sales team is often asked the question: “Should I get a Force Plate, or should I get the AMI?”. Our customers regularly make the mistake that these two products can offer them the same thing. In actuality, these two products hold two very different purposes.

When we consider the Force Plate, its purpose is to capture force data. This they do very well, as such they have been used successfully in research for a long time. However, the main challenge clinicians will face with a Force Plate is: what to do with the data? Clinicians know that when their client’s Force Plate data is off, that something is wrong with their mechanics. But they do not know what. Or rather, the Force Plate does not tell them what or where the system is breaking down. This is where the AMI and Force Plate differ significantly. The AMI consists of wearable sensor technology that has been designed to give clinicians targeted data to help them understand exactly where the movement fault and breakdown occurs in their client’s body. 

Hypothetically, let’s consider an athlete being assessed with a Force Plate and make a basic comparison as to how the data and the clinician’s response would differ from an AMI assessment.

• The athlete is asked to do a Single Leg Hop onto a Force Plate. The clinician reads the data and notices abnormality in the data.
• This is useful information, but it is generalized. The clinician now has to establish where this movement fault is coming from: is it the athlete's foot pronating? Or because the athlete's knee has fallen into valgus? Or is the athlete’s hip falling into a corkscrew?
• The Force Plate data has to be correctly interpreted in order to be beneficial for the athlete and applying this data may not be as specific due to the above reasons.

The AMI measures all these things and, not only can the clinician see it visually, but they can also record it. Let’s maintain our hypothetical example, but with the AMI assessment.

• The athlete will be asked to complete seven research-based tests: Plank, Side Plank, Squat, Single Leg Squat, Single Leg Hop, Single Leg Hop Plant and Ankle Lunge.
• With the AMI, the clinician will be able to see through objective data from the athlete’s Single Leg Hop: whether their knee is falling into valgus position and if the athlete is not controlling the speed of that frontal plane motion.
• With the AMI, the clinician will be able to see through our video setting the athlete’s Single Leg Hop: whether their foot is falling into pronation; they will also see if the issue is lack of pelvic control of the pelvis.
• This allows the clinician to address the weak link in the athlete’s system, from this they can prescribe the correct exercises and offer the athlete the maximum chance of improvement.

Ultimately, unlike the Force Plate, the AMI directs you to what in the system is falling apart and quantifies the data. 

• The AMI assessment also requires athletes to complete these tests with a set number of repetitions, allowing the clinician to see how endurance is impacting the athlete.
• Their Single Leg Hop may look good on the first repetition. On the eighth, ninth or tenth, however, the athlete may present with a significant tibial valgus collapse that needs to be corrected.

Finally, the AMI was designed to be that differential diagnostic process by choosing to take into consideration an athlete’s core stability (yet another challenge a clinician may experience with the Force Plate, which does not take this measurement). The AMI measures core stability through the plank and side plank tests because:

• Lack of core strength, stability and endurance in an athlete can increase their risk for lower extremity injury (Jeong et al, AM J Sport Med, 2020).

The AMI is all about the identification of the weak link in an athlete’s body. This is not the objective of the Force Plate. Instead, the AMI identifies movement faults so clinicians can specifically prescribe and safely address their clients. Fundamentally, comparing these two pieces of technology against each other is as effective as comparing apples to oranges.